<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div></div>
    <script>
        function sum() {
            let num1 = +prompt("请输入第一个数字")
            let num2 = +prompt("请输入第二个数字")
            document.write(`两数之和是${num1 + num2}`)
        }
        sum()
    </script>
</body>

</html>